The present invention relates to a revolving security door for allowing the controlled passage of persons from a non-protected environment to a protected environment, for example a bank, including a cylindrical chamber formed inside a structure, a turnstile rotatable inside the chamber in a predetermined sense of rotation and having sectors each for accommodating a person, the structure being formed with an entry aperture for entry into the chamber from the non protected environment and an exit aperture for exit from the chamber into the protected environment and having a sensor associated therewith in correspondence with the entry aperture for emitting an alarm signal and an emergency door associated with the exit aperture and activated to close by the said alarm signal.
In general, such revolving security doors are intended to control the passage of persons from one environment to another.
In particular, they are commonly fitted where it is necessary to prevent the intrusion of an unwelcome person, for example an armed person, from a non-protected environment, such as a public street, into a protected environment such as the premises of a bank.
Another example of unwelcome person is a person without an appropriate electronic pass or other identification system who attempts to intrude into an environment which may only be accessed by persons provided with the appropriate pass or other identification system.
In a known arrangement, the emergency door is a single panel which closes on emission of the alarm signal and reopens as soon as the sector occupied by the unwelcome person, for example an armed person who sets off the alarm, has passed totally through the exit aperture. This arrangement is satisfactory from the point of view of blocking the access of the unwelcome person but has the disadvantage of blocking the normal transit of persons through the revolving door. In fact, a person who happened to be in the turnstile sector immediately downstream of that occupied by the unwelcome person would find himself at the exit aperture when this was still completely closed and would be unable to get out immediately but would have to wait some time and would then find himself in difficulty on attempting to leave his sector since this would already be moving beyond the exit aperture making this inaccessible.
Therefore, unless he acts extremely fast, the person occupying the turnstile sector downstream of the armed person is also returned to his starting point, along with the unwelcome person.
It has been suggested that the reopening of the emergency door should be speeded up. However, as may be easily imagined, this suggestion involves a series of other disadvantages such as an increase in the dimensions of some parts, more noise and bumps, etc.
A revolving security door has been suggested in which the emergency door is formed by two panels. Clearly such a door would open the exit aperture faster, without the above disadvantage. Unfortunately, however, such a revolving door has the drawback of posing a serious obstacle to access to the sector upstream of that occupied by the unwelcome person, that is by a person wishing to pass in the opposite direction, that is from the protected environment to the non-protected environment.
In fact, the sudden closure of the aperture by the double door leaves hardly sufficient time for entry to the sector and exposes a person attempting to enter to the danger of being struck by at least one door, if not by both.
Time-staggered control of the two panels of the double door does not solve the problem either and would require, in addition, that the turnstile be temporarily stopped or that its rotation be altered.
Therefore a person about to pass through in the opposite direction finds it would be dangerous to enter the first sector and is normally obliged to wait for the sector occupied by the unwelcome person to pass, and possibly for other occupied sectors to pass, before encountering a free sector.
Therefore such a revolving door would also impede normal traffic.
The problem on which the present invention is based is that of devising a revolving door of the type specified above, which has structural and operational characteristics such as to overcome the above disadvantages.